We have this weird situation where the page URL is based on the top of your browser and read state is based on the bottom of your browser.
A change that I made recently made you enter the topic with the post you were linked to scrolled down 20%, which combined with the fact that the URL is based on the top, causes the “moving up” behavior that you describe.
I also get a bit annoyed with the read tracking at times, but I have no clue how to fix it.
Got any ideas? 